The narc fairy comes to visit....

Dave Sutton said:
Yeah... Helium is definately the way to go for RB's... no doubt.
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Well diving Tx at shallow depths is something I hate.
I'll take two bailout stages when needed, but I much prefer to only use an EAN32 down to about 40'ish meters.

I dont mind a bit narcosis, and absolutely hate swimming (and kitting up) with two stages when not needed.

Planned depth below 45 meters and I bring two stages, flick the switch and run Tx as diluent, but ONLY if needed - I much prefer the simplicity and slight buzz of of EAN diving :ocdeath:

But when I finally run Tx18/45 at say 48m, then I absolutely feel like I am at depth 20ish meters.
 
BTW: The reason I asked for vertigo (which was not the case here), Is that a low of divers, especially new ones, experience a sudden onset of vertigo at depth and *wrongly* conclude that they are narced...

They are not! - its alternobaric vertigo which I often experience myself when ascending. It passes quickly, and should not be mistaken for narcosis. I personally think it is made worse when compunded with narcosis, but it is not narcosis per se.
 
matthewoutram said:
Is this in the SCS?
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:thumbsup:
top skipper top boat ,, its a dive boat ,
you eat lunch, and the lads clean your brass from the morning outing ,,

we even had a bit of cordite fun ,,, mmmmmmmmm it lights up the sky at night ,, lol ;)

we also got a fish almost as big as the boat ,,, well the back half of it ,, fun fun fun fish and chips for 10 please ,,
 
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Bythesea said:
...is O2 narcotic? If it were I think we would have scientific proof by now, wouldn't we? It seems a hot topic so surely Rubicon or some such facility would have made a paper....

I don't know but I do know lowering the Nitrogen works a treat....
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Absence of evidence is not evidence of absence. Anecdotal evidence is oxymoronic, it may be interesting to hear but is worthless.

Whether O2 is narcotic is probably only a hot topic on dive forums. :chuckle:
 
nickb said:
I assume you guys don't regard O2 as narcotic for any of this to be relevant (or factual)?

I'm not convinced either way, but I've always calculated narcotic depth as if it is. So, for me, nitrox is as narcotic as air, regardless of depth.

But then, I don't use air as diluent at any depth.
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Your assumption it's right mate :) On the scale from 1 to 5 with 1 been the less narcotic and 5 very narcotic, oxigen and nitrogen are on 4. Now, if the oxygen need to reach the same PP as the nitrogen to be narcotic, let's say at 40 meters, you should be no longer worried about the narcotic effect of the oxygen, because you'll be in Davy Jone's Locker before that

That's why I don't take O2 as narcotic in consideration
 
alin said:
Your assumption it's right mate
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I didn't make an assumption. I said I wasn't convinced either way.

On the scale from 1 to 5 with 1 been the less narcotic and 5 very narcotic, oxigen and nitrogen are on 4. Now, if the oxygen need to reach the same PP as the nitrogen to be narcotic, let's say at 40 meters, you should be no longer worried about the narcotic effect of the oxygen, because you'll be in Davy Jone's Locker before that

That's why I don't take O2 as narcotic in consideration
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You're suggesting that the partial pressures of each individual gas in the mix is what we should use to calculate END - is that right?

So, we could remove some nitrogen from a nitrox mix and replace it with a little argon and it would be less narcotic provided the PPAr remained low enough?
 
nickb said:
I didn't make an assumption. I said I wasn't convinced either way.

You're suggesting that the partial pressures of each individual gas in the mix is what we should use to calculate END - is that right?

So, we could remove some nitrogen from a nitrox mix and replace it with a little argon and it would be less narcotic provided the PPAr remained low enough?
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I take in consideration only the pp of the nitrogen, I don't bother with the narcotic effect of the oxygen. Because as I said, the O2 and N2 have the same narcotic effect. This said, for an END of 40 meters, the PP of N2 will be 3.95. If the O2 have the same narcotic effect, this means that the PP of O2 should reach also 3.95 to have the same effect. And a pp O2 of 3.95 it's a bit much, you're dead before the O2 reach this PP.

Argon it's much more narcotic so even replacing just a little bit of the N2 with Argon, will do nothing but boost up the narcosis. Now wise for breathing but for drysuit inflation only
 
alin said:
I take in consideration only the pp of the nitrogen, I don't bother with the narcotic effect of the oxygen. Because as I said, the O2 and N2 have the same narcotic effect. This said, for an END of 40 meters, the PP of N2 will be 3.95. If the O2 have the same narcotic effect, this means that the PP of O2 should reach also 3.95 to have the same effect. And a pp O2 of 3.95 it's a bit much, you're dead before the O2 reach this PP.

Argon it's much more narcotic so even replacing just a little bit of the N2 with Argon, will do nothing but boost up the narcosis. Now wise for breathing but for drysuit inflation only
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But if argon is 2.5 times as narcotic as nitrogen then, according to your theory, as long as the Ar content remained below around 30% you wouldn't have to consider it.

Do you not consider that narcosis could be a result of the additive effect of all the component gases in the mix?

Your suggestion is akin to saying that 2 beers plus 2 shots plus 2 glasses of wine is the same as 2 drinks.
 
nickb said:
But if argon is 2.5 times as narcotic as nitrogen then, according to your theory, as long as the Ar content remained below around 30% you wouldn't have to consider it.

Do you not consider that narcosis could be a result of the additive effect of all the component gases in the mix?

Your suggestion is akin to saying that 2 beers plus 2 shots plus 2 glasses of wine is the same as 2 drinks.
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No Nick, as more you drink more drunk you'll get and same with the narcotic effect of the gasses. But regarding gasses in the mix, why would you replace a narcotic gas with another one more narcotic? And why I don't take in consideration the O2 as narcotic it's because the pp O2 will stay low enough to have a minor impact. But this is what I'm doing, I'm not saying it's right but it works for me. In an ideal plan we would make for example at least 6 or 7 gas switches for a 100 mt dive. But we don't, we do just 3 or 4 maybe.
 
If O2 and N2 are both equally narcotic then you do not need to treat them separately, you can combine them. 32% Nitrox at 20m is either ppNarcotic=2.04 ([1.0-0.32]x3=2.04) or ppNarcotic=3.00 (1.0x3=3.00)...
 
alin said:
No Nick, as more you drink more drunk you'll get and same with the narcotic effect of the gasses. But regarding gasses in the mix, why would you replace a narcotic gas with another one more narcotic? And why I don't take in consideration the O2 as narcotic it's because the pp O2 will stay low enough to have a minor impact. But this is what I'm doing, I'm not saying it's right but it works for me. In an ideal plan we would make for example at least 6 or 7 gas switches for a 100 mt dive. But we don't, we do just 3 or 4 maybe.
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:rolleyes: I was giving examples as to why I think your hypothesis is ridiculous.

I'll give you the benefit of the doubt and put it down a language barrier that is stopping you understanding that.
 
Bythesea said:
I'm bored of my own thread now, is O2 narcotic? If it were I think we would have scientific proof by now, wouldn't we? It seems a hot topic so surely Rubicon or some such facility would have made a paper....

I don't know but I do know lowering the Nitrogen works a treat....
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Matt told you alredy. In theory, it is. In practic, we don't know and who gives a s...t and who wanna find out should try to go deep with a rich mix. I know I don't wanna do that :)
 
alin said:
Matt told you alredy. In theory, it is. In practic, we don't know and who gives a s...t and who wanna find out should try to go deep with a rich mix. I know I don't wanna do that :)
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That's the way I look at it. Helium costs fook all in a box, why not use it?

Oh yeah, they need to get another couple of hundred quid out of you for the card...

Sent from my GT-I9100 using Tapatalk
 
nickb said:
:rolleyes: I was giving examples as to why I think your hypothesis is ridiculous.

I'll give you the benefit of the doubt and put it down a language barrier that is stopping you understanding that.
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I think I'm understanding it right. But let's not argue mate. To answer to your 1st question, I don't calculate O2 as narcotic.
Happy and safe diving.
 
matthewoutram said:
If O2 and N2 are both equally narcotic then you do not need to treat them separately, you can combine them. 32% Nitrox at 20m is either ppNarcotic=2.04 ([1.0-0.32]x3=2.04) or ppNarcotic=3.00 (1.0x3=3.00)...
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This is exactely what I meant when I wrote "as more you drink more drunk you'll get and same with the narcotic effect of the gasses" but I was missunderstood and the conclusion was that my english sucks :)
 
matthewoutram said:
Once a year I like to bob down to 60m or so on air (usually in blue water), just for the nark. Not quite a GnT, but just as much fun!

Matt.
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Absolutely, just like 3 beers on an empty tum, or that first toke after a hard days surfing. It just hits the spot.
 
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